PHP array addition, deletion and return

PHP is a widely used server-side programming language, and arrays are an important data structure in PHP. In PHP, an array is a container used to store multiple values ​​in a single variable. Arrays make it easier for us to manage and process data. This article will focus on the addition, deletion and return values ​​of PHP arrays.

1. Array creation and access

In PHP, you can create an array in two ways: using the array() function or using square brackets []. The following is a sample code:

//使用 array() 函数创建数组
$myArray = array('苹果', '香蕉', '橘子');

//使用方括号 [] 创建数组
$myArray = ['苹果', '香蕉', '橘子'];

In the above code, the $myArray variable stores three elements: 'apple', 'banana' and 'orange', which correspond to the index values ​​0, 1 and 'orange' in the array respectively. 2. In order to access these elements, you can use the corresponding index value, for example:

//读取数组中的第一个元素
echo $myArray[0]; //输出：苹果

//修改数组中的第二个元素
$myArray[1] = '草莓';

//读取修改后的元素
echo $myArray[1]; //输出：草莓

2. Addition and deletion of arrays

In practical applications, it is often necessary to add or delete elements from an array. operate. The following will introduce how to add and delete arrays:

1. Add elements

You can use array_push(), array_unshift() and direct assignment to add elements. into the array.

Use the array_push() function to add elements to the end of the array, for example:

$myArray = ['苹果', '香蕉'];
array_push($myArray, '橘子');
print_r($myArray); //输出：Array([0] => 苹果 [1] => 香蕉 [2] => 橘子)

In addition, use the array_unshift() function to add elements to the beginning of the array, for example:

$myArray = ['苹果', '香蕉'];
array_unshift($myArray, '西瓜');
print_r($myArray); //输出：Array([0] => 西瓜 [1] => 苹果 [2] => 香蕉)

You can also add elements directly using subscript assignment, for example:

$myArray = ['苹果', '香蕉'];
$myArray[2] = '橘子';
print_r($myArray); //输出：Array([0] => 苹果 [1] => 香蕉 [2] => 橘子)

2. Delete elements

You can use the unset() and array_pop() functions to delete elements in the array .

Use the unset() function to delete the specified element based on the subscript, for example:

$myArray = ['苹果', '香蕉', '橘子'];
unset($myArray[1]); //删除下标为 1 的元素
print_r($myArray); //输出：Array([0] => 苹果 [2] => 橘子)

Use the array_pop() function to delete the element at the end of the array, for example:

$myArray = ['苹果', '香蕉', '橘子'];
array_pop($myArray); //删除最后一个元素
print_r($myArray); //输出：Array([0] => 苹果 [1] => 香蕉)

三, The return value of the array

In PHP, a value will be returned for the addition and deletion operations of the array. The following are the return values ​​in various situations:

1. When using the array_push() function to add elements, the length of the array after adding the elements will be returned.
2. When using the array_unshift() function to add elements, the length of the array after adding the elements will be returned.
3. When adding elements using subscript assignment, no value will be returned.
4. When using the unset() function to delete elements, no value will be returned.
5. When you use the array_pop() function to delete elements, the value of the deleted element will be returned.

Conclusion

Through the introduction of this article, we can clearly understand the addition, deletion and return values ​​of PHP arrays. Array is a very important data structure. For PHP programmers, being proficient in the operation and use of arrays will provide powerful help in developing efficient and stable applications.

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